The use of mobile phones is restricted inside airline carriers due to a possibility that the transmission of a mobile phone could cause interference problems. Anecdotal instances suggest that the use of the mobile phone on an aircraft might interfere with the navigation equipment and other avionics or communications equipment on the aircraft. Another problem is that due to the height of an airborne aircraft the wireless network coverage does not cover the mobile phones on an airborne aircraft because the terrestrial wireless networks are designed for lateral transmission and reception of radio frequency signals and for relatively slow moving vehicles and pedestrians.
Although the use of the mobile phone from an aircraft might be possible at some altitudes, it does not operate within the considerations designed and built about call handovers between adjacent terrestrial cells. Due to the high velocity of the airborne aircraft an equally strong RF signal from the mobile phone may be picked up on multiple base stations on the ground and the network is unable to process a normal call handover procedure. This may result malfunction of operation, dropping calls frequently and can actually cause base stations to shut down. This may also jam calls of other users covered by the same terrestrial base stations.
Today wireless communication services for passengers are provided in aircrafts by dedicated phones that are installed at each seat and wired to the central transmitter/receiver in the aircraft. This network of phones operates on its own frequency band which differs from other frequency bands used for avionics. To run this service a service provider must provide base stations on the ground to which RF signals are transferred in the vertical direction i.e. a skyward transmission and reception. To allow smooth handovers in the air these base stations must cover a much larger territory than the base stations of the terrestrial wireless network and antennas must be focussed skywards. Service users must use the dedicated phones provided by the service provider and users having personal mobile phones in the aircraft must keep their equipment switched off.
One solution for this problem is to provide a base station and thus an internal cell inside the aircraft for communicating with standard mobile phones, and to use satellite communication between the cells of the aircraft and the terrestrial network. This kind of solution is described e.g. in patent document WO 99/12227. However, other problems may arise with such a prior art system.
Firstly, providing a continuous satellite communication causes remarkable costs. If calls are made very seldom, it is practically not possible to cover the costs of a continuous satellite connection from the phone users. On the other hand, a continuous satellite link is required for signalling purposes. It is a very slow procedure to configure a new signalling connection between a base station inside an aircraft and a terrestrial network, so therefore the satellite connection between the base station and the base station controller should not be switched off even if it is not used for transferring calls.
Secondly, a satellite has only a limited operating range. On the other hand, the Airplanes are travelling around the globe, so communication link with one satellite would not be sufficient for providing good quality service for the passengers. It is not either possible to change the satellite link to another satellite because there is no procedure e.g. in the GSM system for changing the BTS location. The BTS-BSC parameters are static and they are related to each other. In an aircraft application there is no information available which satellite and which BSC would be a new target BSC for which BTS should be updated.
A further problem relates to transferring IP (Internet Protocol) data. There is a need to offer passengers of an aircraft a possibility for transferring IP data between their laptops and Internet. At the moment there is no solution on how to provide such a communication inside an aircraft and how to provide the communication of IP data between the aircraft and the Internet.